module/zfs/zio_compress.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 /*
  27  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  28  */
  29
  30 /*
  31  * Copyright (c) 2013, 2018 by Delphix. All rights reserved.
  32  * Copyright (c) 2019, Klara Inc.
  33  * Copyright (c) 2019, Allan Jude
  34  */
  35
  36 #include <sys/zfs_context.h>
  37 #include <sys/spa.h>
  38 #include <sys/zfeature.h>
  39 #include <sys/zio.h>
  40 #include <sys/zio_compress.h>
  41 #include <sys/zstd/zstd.h>
  42
  43 /*
  44  * If nonzero, every 1/X decompression attempts will fail, simulating
  45  * an undetected memory error.
  46  */
  47 unsigned long zio_decompress_fail_fraction = 0;
  48
  49 /*
  50  * Compression vectors.
  51  */
  52 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
  53         {"inherit",     0,      NULL,           NULL, NULL},
  54         {"on",          0,      NULL,           NULL, NULL},
  55         {"uncompressed", 0,     NULL,           NULL, NULL},
  56         {"lzjb",        0,      lzjb_compress,  lzjb_decompress, NULL},
  57         {"empty",       0,      NULL,           NULL, NULL},
  58         {"gzip-1",      1,      gzip_compress,  gzip_decompress, NULL},
  59         {"gzip-2",      2,      gzip_compress,  gzip_decompress, NULL},
  60         {"gzip-3",      3,      gzip_compress,  gzip_decompress, NULL},
  61         {"gzip-4",      4,      gzip_compress,  gzip_decompress, NULL},
  62         {"gzip-5",      5,      gzip_compress,  gzip_decompress, NULL},
  63         {"gzip-6",      6,      gzip_compress,  gzip_decompress, NULL},
  64         {"gzip-7",      7,      gzip_compress,  gzip_decompress, NULL},
  65         {"gzip-8",      8,      gzip_compress,  gzip_decompress, NULL},
  66         {"gzip-9",      9,      gzip_compress,  gzip_decompress, NULL},
  67         {"zle",         64,     zle_compress,   zle_decompress, NULL},
  68         {"lz4",         0,      lz4_compress_zfs, lz4_decompress_zfs, NULL},
  69         {"zstd",        ZIO_ZSTD_LEVEL_DEFAULT, zfs_zstd_compress,
  70             zfs_zstd_decompress, zfs_zstd_decompress_level},
  71 };
  72
  73 uint8_t
  74 zio_complevel_select(spa_t *spa, enum zio_compress compress, uint8_t child,
  75     uint8_t parent)
  76 {
  77         uint8_t result;
  78
  79         if (!ZIO_COMPRESS_HASLEVEL(compress))
  80                 return (0);
  81
  82         result = child;
  83         if (result == ZIO_COMPLEVEL_INHERIT)
  84                 result = parent;
  85
  86         return (result);
  87 }
  88
  89 enum zio_compress
  90 zio_compress_select(spa_t *spa, enum zio_compress child,
  91     enum zio_compress parent)
  92 {
  93         enum zio_compress result;
  94
  95         ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
  96         ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
  97         ASSERT(parent != ZIO_COMPRESS_INHERIT);
  98
  99         result = child;
 100         if (result == ZIO_COMPRESS_INHERIT)
 101                 result = parent;
 102
 103         if (result == ZIO_COMPRESS_ON) {
 104                 if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
 105                         result = ZIO_COMPRESS_LZ4_ON_VALUE;
 106                 else
 107                         result = ZIO_COMPRESS_LEGACY_ON_VALUE;
 108         }
 109
 110         return (result);
 111 }
 112
 113 /*ARGSUSED*/
 114 static int
 115 zio_compress_zeroed_cb(void *data, size_t len, void *private)
 116 {
 117         uint64_t *end = (uint64_t *)((char *)data + len);
 118         for (uint64_t *word = (uint64_t *)data; word < end; word++)
 119                 if (*word != 0)
 120                         return (1);
 121
 122         return (0);
 123 }
 124
 125 size_t
 126 zio_compress_data(enum zio_compress c, abd_t *src, void *dst, size_t s_len,
 127     uint8_t level)
 128 {
 129         size_t c_len, d_len;
 130         uint8_t complevel;
 131         zio_compress_info_t *ci = &zio_compress_table[c];
 132
 133         ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
 134         ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
 135
 136         /*
 137          * If the data is all zeroes, we don't even need to allocate
 138          * a block for it.  We indicate this by returning zero size.
 139          */
 140         if (abd_iterate_func(src, 0, s_len, zio_compress_zeroed_cb, NULL) == 0)
 141                 return (0);
 142
 143         if (c == ZIO_COMPRESS_EMPTY)
 144                 return (s_len);
 145
 146         /* Compress at least 12.5% */
 147         d_len = s_len - (s_len >> 3);
 148
 149         complevel = ci->ci_level;
 150
 151         if (c == ZIO_COMPRESS_ZSTD) {
 152                 /* If we don't know the level, we can't compress it */
 153                 if (level == ZIO_COMPLEVEL_INHERIT)
 154                         return (s_len);
 155
 156                 if (level == ZIO_COMPLEVEL_DEFAULT)
 157                         complevel = ZIO_ZSTD_LEVEL_DEFAULT;
 158                 else
 159                         complevel = level;
 160
 161                 ASSERT3U(complevel, !=, ZIO_COMPLEVEL_INHERIT);
 162         }
 163
 164         /* No compression algorithms can read from ABDs directly */
 165         void *tmp = abd_borrow_buf_copy(src, s_len);
 166         c_len = ci->ci_compress(tmp, dst, s_len, d_len, complevel);
 167         abd_return_buf(src, tmp, s_len);
 168
 169         if (c_len > d_len)
 170                 return (s_len);
 171
 172         ASSERT3U(c_len, <=, d_len);
 173         return (c_len);
 174 }
 175
 176 int
 177 zio_decompress_data_buf(enum zio_compress c, void *src, void *dst,
 178     size_t s_len, size_t d_len, uint8_t *level)
 179 {
 180         zio_compress_info_t *ci = &zio_compress_table[c];
 181         if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
 182                 return (SET_ERROR(EINVAL));
 183
 184         if (ci->ci_decompress_level != NULL && level != NULL)
 185                 return (ci->ci_decompress_level(src, dst, s_len, d_len, level));
 186
 187         return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
 188 }
 189
 190 int
 191 zio_decompress_data(enum zio_compress c, abd_t *src, void *dst,
 192     size_t s_len, size_t d_len, uint8_t *level)
 193 {
 194         void *tmp = abd_borrow_buf_copy(src, s_len);
 195         int ret = zio_decompress_data_buf(c, tmp, dst, s_len, d_len, level);
 196         abd_return_buf(src, tmp, s_len);
 197
 198         /*
 199          * Decompression shouldn't fail, because we've already verified
 200          * the checksum.  However, for extra protection (e.g. against bitflips
 201          * in non-ECC RAM), we handle this error (and test it).
 202          */
 203         if (zio_decompress_fail_fraction != 0 &&
 204             random_in_range(zio_decompress_fail_fraction) == 0)
 205                 ret = SET_ERROR(EINVAL);
 206
 207         return (ret);
 208 }
 209
 210 int
 211 zio_compress_to_feature(enum zio_compress comp)
 212 {
 213         switch (comp) {
 214         case ZIO_COMPRESS_ZSTD:
 215                 return (SPA_FEATURE_ZSTD_COMPRESS);
 216         default:
 217                 /* fallthru */;
 218         }
 219         return (SPA_FEATURE_NONE);
 220 }